Steam-boiler safety device



J. H. STOCKHOLDER ET AL Jan. 31, 1928.

STEAM BOILER SAFETY DEVICE Filed Oct. 18. 1923 F Jan. 31, 19.28.

UNITED STATES PATENT orries.

JOHN H. STOOKHOLDER AND "WILLIAM A. GILES, OF NEW] ORLE.AI\TS,LOUI$IANA. i

STEAM-BOILER SAFETY DEVICE.

Application filed October 18, 1923." Serial No. 669,364.

This invention. relates to steanr boiler safety devices wherein fusible plugs of metal are arranged in the water spaces of steam boilers or steam drums, and are intended to melt at a. predetermined condition of low "ator and "GXCGSRlVQ heat permitting the water aiid steam to escape and to soundan alarm or to act upon the furnace tire to qt ch the same in the manner usual in such devices.

The object of this invention is the production of a safety device belonging to the class stated and having parts of special construction and arrangement whereby it is be lieivcd the cost of manufacture is materially reduced, and the convenience of installation and certainty of operation increased with added effectiveness.

In the accompanying drawings the special construction and arrangement of the parts of this invention are illustrated; Of the drawings, Fig. 1 represents a vertical section lengthwise of all the parts assembled. 2 is a cross-section on the line 2 2 of Fig. 1. hi g. 3 is a bottom view of the casing near the end provided with the out-flow pipe, showing the base or projecting members of the fusible plug carriers. Fig. 4: is a side View of a modified form of this invention.

Throughout the drawings and description the same letter is used to refer to the same part.

Considering Figs. 1, 2 and 3 of the drawings, there will be noted a portion A of the crown sheet of a steam boiler, or other surface thereof subiected to heat. Upon the portion A, and within the water space of the boiler or drum, is placed a casing B of such size and form as will permit its'ar- "augcnient within the water space as de-- sired. The casing has an out-flow pipe 7) wh ch may obviously be led in any direction and may be of such length as may be required. The casing as usually constructed has a number of thickened portions C and through the portions C openings are made and threaded to take the ring nuts or carriers D for the fusible plugs E. The carriers D have on the bottom the spaced members (Z and between them the spaces 6. The members (Z are constructed to make an intimate contact, as close as may be with the heated portion A of the boiler, in order that the temperature of each carrier may at all times be the same as that of the boiler surface of A, the heat being conducted by metallic contact. The members (Z support the casing Band the'plugs E near the surface of the boiler port on A. and in ordinary service the steaming of the boiler causes more orless circulation of water through thespa'ccsc.thereby preventiiig the fasten ing of the carriers D and the plugs E tothe portion A by deposits of boiler scale or the lille. It willhe noted in Fig. 1 that the plug arricr Dhas a coin -al internal chamber corresponding in form to the fusible plug E. It will be observed further thatothe greatest diameter of the chamber is a short distance above the bottom of the carrier D. Below the plug, the spaced members (Z have inwardly prqectmg portions engaging the plug to hold it in position in the opening portions of the plug IE, it is shown that the upper portion a is the longer. -The reason for this construction is that the pressure heneath the plug is relied upon to force the plug into a steam tight fit in the chamber (Z of the carrier, and greater surface of con tact. is desirable, while the lower portion of the plug E, designated by 6 serves by reason of its engagement with the projecting portions (Z of the spaced members cl to prevent the plug from dropping out should it have become loose and when the casing 13 is removed for any purpose. These appli- -ants are fully aware of the practice, and hold themselves at liberty to press the soft metal plugs E into the chambers (Z of the carriers.

The modification illustrated in Fig. il is made up of like parts to those described, but of somewhat different shape. The outflow pipe is marked F, the body of the casing is designated by the letter G, and has side branches 9 and g. The ring nuts H and fusible plugs J are the same as before with the exception that the members h projecting from the base of the carriers are formed to fit a given heated boiler surface, such for example as the fire tube K. The circulation space 7' between the base members 71. will be noted in Fig. 4.

The operation of the preferred form of this invention and of the modification the same. The carriers have at all times the temperature of the surface with which they are in contact, and if there shouldoccur a condition of low water and excessive heat following therefrom, the plugs E soften and blow out into the casing, allowing the steam and Water to escape by way of the out-flow pipes to any suitable alarm. The object of providing a plurality of carriers and plugs is to insure absolute certainty of operation and a higher margin of safety. As illus trated, it is customary to arrange the plugs with like axes thereof in the same plane passing through the casing.

Having now described this invention, and explained the mode of its operation, we claim l In a steam boiler safety device, the coinbination with a casing having an outflow pipe, the said casing lacing constructml l'or arrangement in the Water space of a steam boiler and adjacent to a surface subjected to heat, of a plug carrier having a screw threaded engagement with the said casing,

the said carrier having a conical opening therethrough, a fusible plug fitting the said opening in the carrier, the said carrier having spaced members projecting downwardly JOHN H. STOUKI-lOLlJlfllt.

WILLIAM A. GILES. 

